如何将参数传递给ViewScoped Bean

Brief use-case description:

简要用例说明:

The user arrives to the page: http://localhost:8080/.../show.xhtml?itemId=1. My ShowBean is a @RequestScoped JSF Managed Bean which obtains the id through <f:viewParam.../> and looks for item in the database:

用户到达页面:http:// localhost:8080 /.../ show.xhtml?itemId = 1。我的ShowBean是一个@RequestScoped JSF Managed Bean,它通过获取id,并在数据库中查找项目:

<f:metadata>
    <f:viewParam name="itemId" value="#{showBean.itemId}">
        <f:convertNumber integerOnly="#{true}"/>
    </f:viewParam>
</f:metadata>
<f:event type="preRenderView" listener="#{showBean.init()}"/>

The user can also edit the displayed item. I want to construct the @ViewScoped ItemEditBean on-demand (by clicking on the "Edit" button). To achieve this I did the following:

用户还可以编辑显示的项目。我想按需构建@ViewScoped ItemEditBean(通过单击“编辑”按钮)。为此,我做了以下事情:

<p:commandButton value="Edit" oncomplete="editWidget.show()" update=":itemEditForm">
    <f:setPropertyActionListener target="#{itemEditBean.id}" value="#{showBean.itemId}"/>
</p:commandButton>

My questions are: Is there any better approach to pass itemId to the @ViewScoped bean?

我的问题是:有没有更好的方法将itemId传递给@ViewScoped bean?

EDIT:

Doing itemEditBean.fetch(id) in the action of the p:command button won't initialize the @ViewScoped bean on page rendering.

在p:命令按钮的操作中执行itemEditBean.fetch(id)将不会在页面呈现时初始化@ViewScoped bean。

<p:commandButton value="Edit" oncomplete="editWidget.show()" update=":itemEditForm" action="#{itemEditBean.fetchItem(showBean.itemId)}"/>.

。

With the code above itemEditBean gets constructed on-demand.

使用上面的代码,itemEditBean可以按需构建。

2 个解决方案

#1

I think @ViewScoped is no pro. Try partial form submit. For example like this ,

我认为@ViewScoped不是专业人士。尝试部分表单提交。比如这样,

 <p:commandLink immediate="true" id="addAccessoriesLink" update=":accessoriesEntryForm">  
        <h:graphicImage url="/images/add.png" styleClass="action-img"/>
              <f:setPropertyActionListener value="# AccessoriesActionBean.newAccessories}" target="#{AccessoriesActionBean.newAccessories}" />
  </p:commandLink>

#2

the problem is that showEditBean is re-constructed on INVOKE_APPLICATION in the subsequent request that does not preserve parameters.

问题是showEditBean在后续请求中的INVOKE_APPLICATION上重新构造,该请求不保留参数。

just make sure to preserve them using f:param.

只需确保使用f:param保留它们。

<p:commandButton value="Edit" oncomplete="editWidget.show()" update=":itemEditForm">
    <f:param name="itemId" value="#{showBean.itemId}"/>
    <f:setPropertyActionListener target="#{itemEditBean.id}" value="#{showBean.itemId}"/>
</p:commandButton>

P.S. you were right about @ViewScoped bean lifecycle: it is NOT constructed on page load if appears only in actions!

附:你对@ViewScoped bean生命周期是正确的:如果仅出现在操作中,它不会在页面加载上构建!

#1